Why is it that our telescopes can’t find the “ninth planet”?

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History of astronomy has been a history of receding horizons. The invention of the telescope brought us beyond the ability the naked eye to the millions (and billions) of stars of our milky Way. Use pictures and multi-wavelength astronomy for telescopes has brought us beyond our own galaxy in the distant “island Universes” inhabiting all the space to which we can access. However, despite all that we know about the distant Universe, in our Solar system may be undiscovered worlds. How so?

Why can’t we find a new planet in the Solar system

If scientists can use telescopes to hunt for planets, galaxies, extrasolar planets and other other why can’t they just take and scan our Solar system in search of straying from the center of the “planet X” and other celestial bodies?

There is a key word you need to understand before we take up this question: the value. From the astronomical point of view, each inherent in the object brightness determined by the amount of emitted light. In the case of an object like our Sun, it refers to its own luminosity, because the Sun creates energy and emits it in all directions. In the case of objects like our moon, this is in terms of reflected light, because she has no self-luminosity.

If you look at the moon in the Crescent phase, you will be able to see the surface that is not illuminated by the Sun. It’s not really a trick of the atmosphere of the moon (because she’s practically nonexistent), and the so-called ashen light of the moon: sunlight reflected from the Earth falls on the moon.

The difference in brightness between these two examples shows how big the difference between the reflected light and its own light.

But there is another detail which is emphasized by the differences in brightness between the sun and the Moon, and the Moon and everything else in the night sky. The moon has no right to be brighter than a star, planet or galaxy in the sky, based on their pathetic values. In fact, the Moon is the dimmest object visible to the naked eye from any point on Earth. And yet, it looks brighter everything except the Sun.

The reason for this is that the Moon is very close, and the brightness is not the same as seeing or visible brightness.

The farther the object, the less bright it seems. However, this is not so much a General rule that applies, it is a quantitative relationship that allows us to determine how bright or dim it seems the object depending on the distance to it. Simply put, the brightness (b) falls as the reciprocal of the square of the distance or b ~ 1/r2.

Place the object twice as far and its brightness will fall four times. Place ten times farther and you’ll die a hundred times. Place a thousand times on, the brightness will fall a million times.

For any object that emits its own light, these two factors determine the apparent brightness: the internal brightness and the distance to the observer.

These two factors are arguably the most important to consider when determining the type of telescope that will be built. Want to see something more dull? You will need to collect more light and therefore will need a bigger telescope, or you will have to observe the same point in the sky longer.

If money and technology didn’t matter, you would have to select a great telescope. Assemble the telescope twice, and you will not only collect four times more light, but double the resolution. To collect four times more light, watching longer, you need to spend four times more time and there is almost no increase in resolution.

The biggest telescopes that we have, able to view the objects with the highest resolution possible to determine their items promptly.

There is also the consideration field of view. What is your goal? To see the dim object possible? Or see the maximum field of the Universe?

There will have to compromise. Your telescope can collect a certain amount of light, viewing a small area with high accuracy or a larger area with some precision. Just as the microscope can double the magnification, halve the diameter of the field of view, the telescope can look deeper in the Universe, narrowed his field of vision.

Various telescopes optimized for different purposes. But the compromise is very serious. If we want to look as deeply as possible, we have to choose a very small region of the sky.

It kablovske extremely deep field. A tiny region of space visible at different wavelengths, a total of 23 days. The amount of information we fished, just striking: we found 5,500 galaxies in this tiny patch of sky. The dim objects in this piece literally 10 000 000 000 times weaker than what you can see in the naked eye.

Thanks to a mirror of large diameter, the observations at different wavelengths, location in space, a large magnification and a small field of view, Hubble was able to detect the fainter galaxies, which only you can see. But this is the price: this image, which took 23 days, includes only 1/32 000 000 part of the sky.

On the other hand, you can see that. This picture was taken with a telescope, Pan-STARRS, which is every night loops through all the visible sky from his seat on the Ground. It is comparable in size with the space Hubble telescope, but optimized for shooting wide field, choosing a larger coverage of the sky instead of increasing.

As a result, it can detect objects located in almost any part of the sky; only the extreme South pole cut off due to the location of the telescope in the Northern hemisphere. Pan-STARRS captures 75% of the sky and perfectly captures changes between points of light. He can find comets, asteroids, Kuiper belt objects, and much more. But these objects must be thousands of times brighter than the dim one of those that finds the “Hubble”.

As much as we want to, we can’t just explore the outer Solar system with the necessary approach to find all that is in it. Deep, smartply overview of the entire sky that will likely never be possible due to technological restrictions; we can see a dim in the narrow range in bright or wide, but not both simultaneously.

There is also another limiting factor, which goes back to the beginning: these objects only reflect the light of the sun. If you look at the outer Solar system into two identical object, but one is two times further than the other, it will be sixteen times dimmer. This is due to the fact that eventually the sun will Shine on a distant object and that becomes brighter in the quarter, but then the reflected light must pass two more distance to our eyes, resulting in the overall apparent brightness decreases as b ~ 1 / r⁴. Even if the Oort cloud was the world the size of Jupiter, we would not have found it.

We have many telescopes that can see incredibly dim objects, but we need to know where to send them. We have a variety of telescopes, able to survey huge areas of sky, but they can only see bright objects, and not the weak. As for objects in our own Solar system because they reflect light, not emit its own which cannot be seen in any modern telescope, if they are over a certain distance.

It turns out that despite all our knowledge about the Universe and our own planet, the outskirts of our Solar system can always remain for us a fount of surprises.

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